Telephone-exchange system.



A. E. LUNDELL.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED N0v.2, I9I7.

1,278,697, Pafentdsept. 10,1918.

3 SHEETS-SHEET l.

ffy.

ms persas co., naam-urso., wAsmNcmN. nv r:v

A. E. LUNDELL.

TELEPHONE EXCHANGE SYSTEM.

APPLlcAjloN FILED N0v.2, |911.

1,278,697. Patented sept. 10,1918,

3 SHEETS-SHEET 2.

jama.. il n =I L iul ufl z5 U,A Wig@ lega? l l /4/e/7 f. ande/ b2. IH 3.

A. E. LUNDELL.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED Nov.2. 19H.

Patented Sept. 10, 1918.

3 SHEETS-SHEET 3.

`l l U2. ll. 5

l -ms mmms persas ca. vuomuma.. wnsumamw, n. c.

UNETED aTEs raTENT ernten.

ALBEN E. LUNDELL, 0E NEW YORK, N. Y., AssIGNOR To WESTERN ELECTRIC COM-PANY, INCORPORATED, 0E NEW YORK, N. Y1, A CORPORATION OE NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent'. Patented Sept. 10, 1.918.

Application filed November 2, 1917. Serial No. 199,865.

T0 all whom t may concern Be it known that l, 4ALBEN E. LUNDELL, acitizen of the United States, residing at New York, in they county ofBronx and State of New York, have invented certain new and usefulImprovements in Telephone- Exchange Systems, ofwhich the following is afull, clear, concise, and exact description.

This invention rrelates to telephone exchange systems, and moreparticularly to means for establishing a talking connection between aconnecting operator and a subscriber.

lt is the object of this invention to provide improved means toestablish connection from an operators telephone head-set to a desiredlink circuit, such means being arranged so as to establish connectionsquickly and with a small amount of apparatus.

In telephone systems of the semi-automatic type, it has been frequentpractice to provide each operator with a plurality of link circuits andto associate with each of said link circuits an auxiliary switch to beused in Yestablishing connection from said link circuits to saidhead-set.

More specifically, it is the object of this invention to provide anarrangement in which a relatively small number of auxiliary switcheswill be needed to control the connections between the operators head-setand the cords at her position.

The cord circuits of al position are divided into groups and associatedwith each group is an auxiliary automatic switch. ln addition there isanother automatic switch which we will call a central auxiliary switch.All these switches are arranged to be operated in a hunting movement,the operation being such that when connection from a particular cord tothe head-set is desired, all. the switches will rotate in a huntingmovement, the central switch establishing connection from the head-setto the switch associated with the desired group of linkl circuits, andthe selected auxiliary group switch will then determine to which circuitin the group the headset connection will be further extended.

The saving in the number of switches required, accomplished by thisgrouping arrangement, will be more obvious from the followingconcreteexample. If we assume that there are twenty-five cord circuits at ancperatoi"s pesition, and 'that these are divided into five groupsof tiveeach, there will be required only one auxiliary switch for each group,in addition to the control auxiliary switch, or a total of six switchesas against the twenty-tive switches which would ordinarily. be required.

In previous grouping arrangements of this kind, listening-in wasaccomplished automatically when the operator answered a callby plugginginto the jack of the call'- ing line, but if she desired to relisten in,it was necessary for hereto press a listening key and hold it depressedfor a suiicient length of time to allow the switches to establish thedesired connection.

- A feature of the present invention is an arrangement by which themomentary depression of a Ylistening key will cause locking relays tooperate and maintain the registration Ynecessary to cause the properswitchesy to find the desired cord.

A further feature of the invention is the cordinate arrangement of saidlocking re- I lays so that by energizing a plurality of relays each timea key is depressed, the numberV of lockingv relays required will becon-` siderably less than the number of keys.

Further features of the invention reside in the provision of means fordisconnecting the head-setfrom the contacts of the hunting switcheswhilcjthe switches are in motion, in the provision of means forreleasing the locking relays at desired times and in other improvementswhich will appear vfrom the following description.

It is thought that the invention will be best understood from thefollowing detailed description, reference being had to the accompanyingdrawings., l

ln the drawings, Figure l shows a connecting operators cord circuit,together with the diagrammatic indication of an automatic switch forextending a desired connection, together with an associated sequenceswitch for controlling said selector switch. Within the dotted rectanglein the lower portion of Fig. l is shown a portion of ka sendingequipment of a well known type and controlled by a sequence switch, notshown. Fig. 2 shows the listening keys and the locking relays whichcontrol the auxiliary switches. F ig. 3 showsthe auxiliary switches andthe operators head-set.

Theswitch diagrammatically indicated inv Fig. l is similar in structureto thatshown in PatentgNo. 1,123,696, issued January 5,

llO

is similar to that described in Patent No.i

1,168,319, which issued to applicant on January 18, 1916. The-auxiliaryswitches shown in Fig. 3 are of the well-known sequence switchV type asdisclosed in the above mentioned Patent No. 1,127,808.

It will be assumed thaty the operator, one of whose cord circuits isshown in Fig. 1, has at her position twenty-four cords, and

thatthese cords are divided into four groups of five cords each and onegroup of fourA cords. There will be a listening key associated with eachcord and with kfive group switches and one central switch, twenty-fivecombinations may bev established. The twenty-'fifth combination will.control the listening-out condition and will be controlled by alistening-out key. I

The operation is' as follows: Vrlhe Vsubscriber at substation 1 desiringa connection, removes his receiver from the hook, whereupon line relay 2will be energized to cause the display of line signal 3 in a wellknownmanner. The operator, o-ne of whose cord circuits is indicated at O,upon observing the lighting of lamp 3, insertsplug 4 into jack 5 of thecalling line. A circuit is then completed from grounded battery, windingrof relay 6, ,sleeve contacts of lug 4 and jack 5, winding of cut-offrelayg to ground. Cut-olin relay 7 is energizedr to remove control ofthe line relay from the calling subscriber in the well-known manner.Relay 6 '1s also energized and completes a circuit from groundedbattery, power magnet of sequence switch 8, upper right-hand contact ofsequence switch spring 9, armature and front contact of relay 6 toground,

for moving sequence switchf8 out of position 1 and into position 2.

When sequence switch 8 passes through positions 1ito lf-,a circuit iscompleted from grounded battery, winding of cord relay 10, conductors 11and 12, contact of sequence switch spring 13, conductors 14 and 15,left-hand winding of 4group relay 16, winding of relay 17 tov ground.Relays 10,

- 16 and 17 are energized in this circuit. Re-

lay 16 upon energization completes a locking circuit for itselfextending from grounded battery, right-hand armature and front contactof relay 16, armature and back con-- tact of relay 18 to ground. Relay10 upon energization completes a locking circuit for itself, extendingfrom grounded battery, winding of relay 10, left-hand armature and frontcontact of relay 10, winding of relay 19 to ground at the armaturevandback contact of relay 18. Vhen sequence switch 8 leaves position 1%, theoriginal energizing circuit of relays 10, 16 and 17 is broken and relay17 denergizes, but relays 10 and 16 aremaintained energized by means ofthe above described locking circuits.

With relay 19 energized and relay 17 deenergized, parallel circuits arecompleted for the power magnets of sequence switches 20, 21, 22, 23, 24and 25 respectively. These circuits extend from grounded battery,through the power magnets of said switches respectively, through theright-hand armatures and back contacts of cut-ofi1 relays 26, 27, 28,29, 30and 31, respectively, to conductor 32, armature and` front contactof relay 19 and armature` and back contact of relay 17 to ground. If itis assumed that the cord'circuit shown in Fig. 1 is the first cord inthe iirst gro-up, then when groupswitch 21 arrives in position 1, acircuit will be completed from grounded battery, winding ofrelay 27,upper right-hand contact of sequence switch spring 33, conductor 34 toground at the right-hand armature and front contact of relay 10.Similarly sequence switch 22 will be stopped vin position 1 by `theactuation of relay 28, sequence switch 23 will be stopped in position 1by the actuation of relay 29, sequence switch 24 in position 1 by theactuation of relay 30 and sequence switch 25 in position 1 by theactuation of relay 31. Central switch 20 will be stopped in position 1to extend the Vheadset connections to the first group switch, which isswitch 21, by means of the actuation of relay 26 overv a circuitextending from grounded battery, windingV of relay 26, upper right-handcontact oi" sequence switch spring 35, conductor 36, lett-handV armatureand front contact of relay 16 to ground. As soon as all the auxiliaryswitches have been positioned, acircuit will be completed from groundedvbattery, winding of relay 18, conductor 37, left-hand armature and frontcontact of relay 27 upper righthand contact of sequence switch spring38, left-hand armature and front `contact of relay 26 to ground. At thesame time, a parallel circuit is completed from grounded battery,winding of relay 39, conductor 40, left-hand armature and front contactof relay 27, upper-right-hand contact of sequence switch spring 38,left-hand armature and front Contact of relay 26 to ground. Theenergization of relay 39 extends the headset connections to switchsprings .41 and 42 and since the central auxiliary switch 20 `is in itsiirst position, connection willthen be extended to the contacts of groupauxiliary switch 21. This switch being also in position 1, the head-setconnections will be further extended by way of contacts 43 and 44 andconductors 45, 46 to the desired vcord circuit. Relay 18 uponenergization opens the locking circuits of relays 16, 10 and 19 andthese relays denergize. Denergization of relays 10 and 16 causes in turnthe deenergization of relays 26, 27, 28, 29, 30 and 31. Relay 39 ismaintained energized by means of a locking circuit extending fromgrounded battery, winding of relay 39, outer left-hand armature andfront contact of relay 39, conductor 47, larmature and back contact ofrelay 17 to ground. Relay 18 is maintained energized in a branch of thislocking circuit extending from grounded battery, winding of relay 18,conductors 37 and 40, outer left-hand armature and front contact ofrelay 39 and thence to ground over the path described.

The connection between the calling subscriber and the operator is nowcomplete .and may be traced as follows: from the operators receiver 48,winding of induction coil 49, inner left-hand armature and front contactof relay 39, upper left-hand contact of switch spring 41, the upperright-hand contact of switch spring 44, conductor 46,

ring contacts of plug 4 and jack 5 through the loop of the. callingsubscribers line, including the substation apparatus, tip cong tacts ofjack 5 and plug 4, conductor 45, upper right-hand contact of switchspring 43, upper left-hand contact of sequence switch spring 42,right-hand armature and front contact of relay 39, condenser 50 andthence toreceiver 48. Talking batteryis supplied to the callingsubscriber from the battery shown connected to the windings of repeatingcoil 51. ,Talking battery for the operator is included in series withthe primary winding of induction coil 49 and the transmitter of theoperators telephone set.

The operator may now converse with the calling subscriber and ascertainthenumber of the wanted line. She will then proceed, as described in thepreviously mentioned Patent No. 1,168,319, to set up a number on a keyset (not shown) to control the switch indicated in F ig. 1 and othersucceeding switches.

`Assuming that sequence switch 8 is advanced to position 11 after theoperation of the selector switch whose brushes are generally indicatedat 52, the circuit for controlling` the succeeding switches will beextended by means of the lower contacts oitY sequence switch springs 53and 54 to the sender indicated generally at 55.

When the sequence switch associated with the sending device reachesposition 16, at which time the succeeding switches of the train willhave been positioned, a circuit is completed from grounded battery,power magnet of sequence switch 8, lower left-hand contact of sequenceswitch spring 9, contact of sequence switch spring 56 to ground, formoving sequence switch 8 out of position 11 and into position 16, inwhich position talking may take place. Upon completion of theconversation the replacing of their receivers by the calling and called.subscribers will operate supervisory signals of the wel -lmown type,which signals are Controlled by supervisory relays 57 and 58,respectively. The operation of these signals will inform the connectingoperator that connection is no longer desired and she will thereupontake down the connection vby removing plug 4 from jack 5. The. removalof plug 4 from jack 5 causes the denergization of relay 6, whereupon acircuit is completed from grounded battery, power magnet of sequenceswitch 8, upper left-hand contact of sequence switch spring 9, armatureand back contact of relay 6 to ground, for moving this sequence switchout of position 16 and into position 18.

In position 18, the selector switch 52 and the other switches of thetrain are restored in the well-known manner. When the selec-k tor switchindicated at 52 is returned to its normal position, suitable circuitswill be set up for advancing sequence switch 8 into position 1, inreadiness for reoperation of the selector switch.

It will now be assumed that the connecting operator, after setting uptheconnection just described, answers a call with cord 19. Vhen thesequence switch associated with cord 19 Ipasses through positions l?? tol, a circuit will be completed from grounded battery, winding of relay57, conductor 58, through the contacts of a sequence switch springcorresponding to spring 13 in Fig. 1, conductor 59, left-hand winding ofrelay 60, winding ofv relay 17 to ground. Relays 57, 60 and 17 areenergized and relays 57 and 60 lock up kover circuits similar to thosedescribed for relays 10 and 16. At this time the energization of relay17 will open the. locking circuits of relays 18 and 39 and these relayswill be denergized. The energized condition of relays 57 and 60, withrelay 19 energized and relay 17 denergized, will again complete circuitsfor starting the auxiliary switches. This time the central switch 20will be stopped in position 4 to select the fourth group, and groupauxiliary switches 21, 22, 23, 24 and 25 will be stopped in position 4to select the fourth cord in the fourth group. Thus it will be seen thatin answering another call the operator has been automatically listenedout of the cord shown in Fig. 1 and listened in on cord 19.

It now she desires to rclisten in on cord No. 1 she will depresslistening key No. 1, whereupon circuits for-relays 10, 16 and 17 will becompleted as previously described, excepting that instead of extendingthrough the contacts 0I" sequence switch spring 13, connection will bedirectly extended from conductor 11 to conductor 15 through the closedcontacts of listening key No. 1. Since the actuated relaysare locked upinstantly, it is obvious that only a momentary depression of thelistening key is necessary.

It is to be observed that relay 39 is deenergized during the huntingmovementof the switches and therefore the head-set connections are notextended to the wipers of the hunting switches, thus preventing clicksas the switches pass over contacts leading to busy cords. l y

It will also be noted that by arranging the locking relays on acordi'nate basis, that is, pulling up two relays each time that a keyisdep'ressed, the number or" relays required is rela-tively few incomparison to the number of keys. f

It is obvious that listening-outv may be accomplished at any desired'time by causing the switches to move into positions such that thehead-set connection will simply vbe extended to unwired contacts on acord selecting switch. In the arrangement shown it has been assumed thatkev No. 25 is Vthe listening-out key and therefore the contacts closedin position 5 of the cord selecting switch 25, will not be wired,-

It is to be understood that the grouping arrangement shown i's merelyassumed for the purpose of giving clarity to the description and thatany desired number of groups and any number of cords in a group arearrangements within the spirit of the present invention.

What lis claimed is:

1. In a telephone exchange system, a plurality of link circuits arrangedin groups', anv operators telephone set, a listening key associated witheach of said link circuits, means to extend connection from saidtelephone set to a ldesired group, means to further extend saidconnection toa desired link circuit in a selected group,and means opera#tive upon a momentary depression or one of said listening keys toestablish connection from said telephone set to a desired link circuit.y

2. In a telephone exchange system, a plurality of link circuit-sarranged in groups, an operators telephone set, means to extendconnection from said set to a desired group, means to further extendsaid connection to a desired 'cord in a selected-group, means to.

automatically establish a listening-in con# nection when said operatoranswers a call,-

a listening key associated with each link circuitcord, means toautomatially listen in on a second 'cord when takenl for use, and meansoperative upon a momentary depression of one of said listening keys toestablish connection from said head-set to the link circuit with whichsaid depressed key is associated. l

In a telephone elchangesystem, a plurality of link circuits arranged invgroups,

an o'perators telephone set, a listening key associated with each ofsaid link circuitsIl mea'nsftoV `extend `connection from'said teleplionesetto a desired group', means to further extendV connection to a desiredlink circuit int a selected group, means to automatically establish' alistening-,in connection to a link circuit when takenti use, means toauto# niatically disconnect said head-set from said irstflink circuitwhen a second link circuit is taken for use, means to'automaticallvestablsh connection from said head-set to said second linkcircuit, 'and means operative upon a momentary depression of one ofAsaid listening keys to estab'lishconn'ection from said telephone set toa desired link circuit.

l. In a telephone exchange system, a plurality of link circuits arrangedin groups an automatic .switch associated with each oi said groups, anadditional automatic switch, an operators telephone set, a .listeningkey associated with each of said link circuits, means to operate 'saidadditional switch to extendl connection from said telephone set to adesired group switch, means to operate a selected groupY switch tofurther extend said connection to a' desired link circuit, and meansoperative upon momentary depression of one 'of said listening keys toestablish connection from said telephone set to a desired link circuit.i

5. In a telephone exchange system, a plu-V rality oi link circuitsarranged in groups, an automatic switch'gassociated with each of saidgroups, an Vadditional automatic switch, an operatoidstelephone set, akey associated with each of said link circuits, and means including saidswitches to extend connections from said telephone set to a desired linkcircuit under the control of the key associated with said linkv circuitupon a momentary depression of said key.

6. In a telephone exchange system, a plurality of link circuits arrangedin groups, an operators telephone set, a key associated with each ofsaid link circuits, a plurality of relays, means to' actuate certainones of said relays upon a momentary depression of one of said keys, andmeans to establish connection from said head-set to a desired linkcircuit in accordance with which ones ot said relays have been actuated.

7. In a telephone exchange system, a plurality of link circuits arrangedin groups, an automatic switch associated with each of said groups, anadditional automatic switch, an operators telephone set, a keyassociatedwith each of said link circuits, a'plurality of relays, means to actuatecertain ones of said relays upna momentary depression of one of saidkeys, means to operate said additional switch to extend v connectionfrom said telephone set to a desired group switch, means to operate aselected group switch to further extend said connection toa desired linkcircuit, and means to control the extent of motion of said switches inaccordance with which ones of said relays have been actuated.

8. In a telephone exchange system, a plurality of link circuits, aplurality of automatic switches, an operators telephone set, a pluralityof locking relays less in number than said link circuits, means toactuate said automatic switches under the control of said locking relaysto extend connection from said telephone set to a desired link circuitthrough contacts of two of said switches in succession, and means tocontrol the extent of movement of said switches in accordance with theactuated or non-actuated condition of said relays,

9. In a telephone exchange system, a plurality of link circuits arrangedin groups, an operators telephone set, a primary automatic switch toextend connection from said telephone set to a desired group, asecondary automatic switch individual to each group, a key associatedwith each of said link circuits, a group of locking relays to controlgroup selection, a secondary group of locking relays to controlindividual link selection, means to actuate a relay in each of saidgroups upon momentary depression of one of said keys, means to controlthe extent of movement of said primary switch in accordance with whichone of said group selection controlling relays has been actuated, andmeans to control the extent of movement of said secondary switches inaccordance with which one of said individual link selection controllingrelays has been actuated, to extend connection from said telephone setto a desired link circuit.

In witness whereof I hereunto subscribe my7name this 27th day ofOctober, A. D. 191

ALBEN E. LUNDELL.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

